1. Field of the Invention
The invention relates to a self-centering steady rest for clamping and/or holding a workpiece on a turning machine. The steady rest is provided with three holding elements mounted in a housing of the steady rest and held adjustably in a common plane, of which two outer holding elements are configured as swivelling angled levers supported in the housing and in a mirror-image arrangement with one another, and the middle holding element is guided in the housing by means of a drive unit and a middle piece in a driveable connection with the drive unit in such a way as to be axially moveable in the direction of the workpiece, with control surfaces being provided on the middle piece, in which case the two outer holding elements interact with the control surfaces by means of inner ends of the holding elements.
Steady rests of this kind have been produced by the Applicant for decades and have been marketed successfully.
For example, a steady rest of this kind is disclosed in EP 0 562 180 B1.
2. Description of the Prior Art
Generally these steady rests are driven by a pressure piston, by means of which the middle piece is moved axially in the direction of the workpiece to be clamped, either forwards or backwards from the workpiece. The pressure piston in this case has hydraulic fluid acting on it, with the effect that the pressure piston performs the forwards and backwards movements required for clamping and unlocking movements.
For decades now, there has been a significant requirement for a different kind of drive device to be provided as an alternative to the hydraulic drive with pressure piston which has been disclosed.